Because both friction and load are calculated in units of force (such as pounds or newtons), the coefficient of friction is dimensionless. This constant ratio is called the coefficient of friction and is typically symbolized by the Greek letter mu (μ). Thus, the ratio of friction F to load L is the same. If a load of three bricks is pulled along a table, the friction is three times more than if one brick is pulled. Second, friction is directly proportional to the weight that presses the surfaces together. If a brick is pulled along a table, the frictional force is similar whether the brick is lying flat or standing on end. First, the volume of friction is nearly independent of the area of contact. Two basic experimental facts describe the friction of sliding solids. The full amount of friction force that a surface can apply upon an object can be easily measured with the use of the given formula: If an object is pushed against the surface, then the frictional force will be increased and becomes extra than the weight of the object. If an object is placed against an object, then the frictional force will be the same as the weight of the object.
